1. Field of the Invention
The present invention relates to an optical fiber composite ground wire including a protective tube containing a grooved conductive spacer, and a method of manufacturing the same.
2. Related Background Art
An optical fiber is free from electromagnetic induction interference in spite of its large information transmission capacity. Owing to such characteristics, the optical fiber can be incorporated in an aerial cable or a general power line. Therefore, a communication cable need not be separately installed. There is proposed a structure for incorporating such an optical fiber cable in an aerial cable, in which part of a stranded conductor is replaced with an optical fiber cable unit.
A conventional optical fiber composite ground wire and its manufacturing method are known (Japanese Patent Laid-Open No. 58-7607). In this wire, an optical fiber unit is arranged in a helical groove, formed in a spacer, together with a jelly, and a metal film is formed on the outer surface of the spacer.
According to the above-described related art, in the process of forming a metal film on the outer surface of a spacer, when a plate-like conductor is processed by roll forming, and the butted portions of the conductor are welded, a jelly enters a weld point to cause variations in welded state, resulting in a defective product.